How to Spot China's New Space Laboratory in Night Sky

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Over the last 13 years skywatchers have had the opportunity to
watch the world's largest man-made object in space, the
International Space Station, take shape. As the space station
gradually grew in size, observers here on Earth could see it
become steadily brighter as it sailed across the twilight
sky.

Occasionally, it would be accompanied by a second object, usually
the space shuttle, ferrying astronauts and cosmonauts to the
station or back to Earth. With the construction of the space
station finally completed this summer, as well as the end of the
30-year-old space shuttle program, attention now turns to a new
space facility currently orbiting the Earth.

Longtime satellite observers may recall when, in late November
1998, the first segment of the International Space Station,
"Zarya," was launched from Russia. The spacecraft soon became
visible as a bright "moving star" in the sky. Now, in a similar
fashion, Tiangong 1 is visible as a bright, starlike object
tracking across the sky.

Tiangong 1 is expected to be joined soon by three separate
unmanned Chinese spacecraft —
Shenzhou 8, Shenzhou 9 and Shenzhou 10 — that will mark
China's first attempt at docking maneuvers in space.

When this happens, there will be opportunities to see two Chinese
spacecraft flying in tandem, reminiscent of when the space
shuttle and the International Space Station could be viewed
before docking or just after undocking. [ Photos:
Spotting Spaceships & Satellites from Earth ]

Shenzhou 8 is expected to be launched on a 12-day mission
sometime in November, while Shenzhou 9 and Shenzhou 10 are
scheduled to lift off during 2012. One or both of these
latter missions may carry the first astronauts to
Tiangong 1.

Regions of visibility

The International Space Station orbits Earth in a 51.6-degree
inclined orbit, 233 miles by 248 miles (376 by 399 kilometers)
high and is visible from 95 percent of the inhabited land on
Earth.

But Tiangong 1 orbits Earth at a somewhat lower inclination of
42.8 degrees and at a lower 122-by-214- mile (197 by 345
kilometer) altitude. As such, it is visible from about 80
percent of inhabited land areas.

For places north of about latitude 60 degrees north, Tiangong 1
will never rise above the horizon to be visible. This includes
much of Alaska, the northern half of Canada, Iceland, Norway,
Sweden and Finland. And for places just a short distance farther
to the south, such as Juneau, Edmonton, Dublin and Copenhagen,
Tiangong 1 will never get very high above the southern horizon;
an altitude of less than 10 degrees (the apparent width of your
clenched fist held at arm's length).

But for those regions of the globe between 42.8 degrees south
(near Christchurch) to 42.8 degrees north (near Boston), Tiangong
1 can occasionally appear to arc high across the sky, even
passing directly overhead at times.

What to look for

The appearance of this newly launched Chinese spacecraft moving
across the sky is not in itself unusual.

Truth be told, on any clear evening within a couple hours of
local sunset and with no optical aid, you can usually spot several
orbiting Earth satellites creeping across the sky like moving
stars. Satellites become visible only when they are in sunlight
and the observer is in deep twilight or darkness. This usually
means shortly after dusk or before dawn.

What makes these upcoming passes so interesting is that you'll be
able to see China's first space laboratory module, which is
expected to set the stage for the future of that country's
ambitious space program — an important part of China's
stepping-stone strategy to human spaceflight.

This week, it should be visible at dusk as an evening object
across most the United States and southern Canada, as well as
southern Europe.

And this is a sight that should be easily visible to anyone, even
from brightly lit cities. Tiangong 1 was observed on Oct. 1 by
veteran Italian satellite observer Simone Corbellini who said its
"brightness (was) steady at about magnitude 2; easily visible
with the naked eye."

Magnitude 2 is as bright as Polaris, the North Star, on
astronomers' brightness rating scale, where brighter objects have
lower magnitude numbers. Some have suggested that Tiangong
1 could shine as bright as a star of first magnitude, which would
rank it among the brightest stars in the sky.

When and where to look

To find out the best time to view Tiangong 1 from your hometown,
visit one of these two websites:

Each will ask for your ZIP code or city, and respond with a list
of suggested spotting times. Predictions computed a few days
ahead of time are usually accurate to within a few minutes.
However, they can change due to the slow decay of the object's
orbit, so check frequently for updates.

Another great site is this
one, which provides real-time satellite tracking and shows
you at any given moment during the day or night over what part of
the Earth the International Space Station happens to be.

Musical mystery

Perhaps the biggest oddity surrounding Tiangong 1 deals with
music. On Sept. 29, Chinese state broadcaster CCTV and the
Chinese space agency collaborated on a short video to mark the
liftoff of Tiangong 1. The 98-second video gave an animated look
at the launch and China's plans for a possible space station —
all set to an instrumental version of "America the
Beautiful."

Why? Nobody seems to know. Even the CCTV propaganda department
was unable to provide an answer.

Interestingly, on April 24, 1970, when the People's Republic of
China placed its very first satellite in orbit, it, too, had a
musical theme. In the June 1970 issue of Sky & Telescope,
Raymond N. Watts Jr. of the Smithsonian Astrophysical Observatory
wrote:

"The spacecraft is too faint to be seen with the naked eye, but
could be heard on 20,009 megahertz broadcasting the song 'Tung
Fang Hung' (The East is Red), the semiofficial anthem of Red
China."

Editor's note: If you snap a great image of China's Tiangong 1
based on the skywatching website data above and would like to
share it for a possible image gallery or story, please contact
managing editor Tariq Malik at tmalik@space.com.

Joe Rao serves as an instructor and guest lecturer at New
York's Hayden Planetarium. He writes about astronomy for The New
York Times and other publications, and he is also an on-camera
meteorologist for News 12 Westchester, New York